Granite belongs to igneous rock, which is composed of quartz feldspar. Its hardness reaches about hs7-8, which is very close to diamond. Granite has higher hardness than marble, so it is difficult to process, but it is resistant to acid, weathering and corrosion. It is not easy to be weathered and metamorphosed, and its appearance color can be maintained for more than 100 years. Therefore, granite caves are used as protective shelters for important national nuclear military equipment in modern times to avoid being damaged in wartime.

花岗岩的特性，的耐磨损性，耐腐蚀，韧性好，抗风化，吸水性较好，十分适合做石磨，故花岗岩石磨为石磨鼻祖。色泽光度可保持千百年以上，的“埃及金字塔”“古希腊神庙”“北京人民英雄纪念碑”均很多使用花岗岩，保证千百年后留给后人无缺如初。

Granite features excellent wear resistance, corrosion resistance, good toughness, weathering resistance, good water absorption, it is very suitable for making stone mill, so granite stone mill is the ancestor of stone mill. The color and luminosity can be maintained for more than a thousand years. The famous "pyramid of Egypt", "ancient Greek temple" and "monument to the people's Heroes in Beijing" all use granite to ensure that there will be no shortage for future generations after thousands of years.

青石归于碳酸岩硬度较低，硬度一般为2-2.6左右，青石材质较脆，耐磨性和抗风化性较差，色泽也只能到达50%左右，抛光后作用不理想，长处：自然界存量遍广，全国本钱较低，对制作工人要求也不高，适合厂家量大出产。

Bluestone belongs to carbonatite, the hardness is generally about 2-2.6, bluestone material is brittle, the wear resistance and weathering resistance is poor, the color can only reach about 50%, the effect after polishing is not ideal, advantages: the natural stock is wide, the national capital is low, the requirements for the production workers are not high, suitable for large-scale production.

青石的比砂岩的好，由于青石的硬度比砂岩的高，砂岩吸水，不耐风化，容易碎，硬度低，研磨性差，仅仅容易挖掘和制造而言。

Bluestone is better than sandstone. Because bluestone has higher hardness than sandstone, sandstone absorbs water, is not resistant to weathering, is easy to break, has low hardness and poor abrasiveness, and is only easy to excavate and manufacture.

杂粮加工，这里讲的是将小麦、玉米进行简加工，通过面粉机或者玉米脱皮抛光机、制糁机加工成用于食品、饲料、化工等等各个领域的原料。小麦可以加工成精粉、特一粉、通粉等各个不同精细和要求等级的面粉，玉米经过加工可以成为大、中、小及粉状的颗粒，这些加工后的产品都可以用于日常生活和化工科学领域等各个方面，可谓是市场非常的广泛，需求量也是非常之大，人人离不开小麦，人人离不开玉米。所以说，选择这一行，不会有错的，有需求就会有市场。

Coarse cereals processing, here is about wheat, corn simple processing, through flour machine or corn peeling polishing machine, grits machine processing for food, feed, chemical and other fields of raw materials. Wheat can be processed into refined flour, special one flour, Tong flour and other different fine and required grades of flour, corn can be processed into large, medium, small and powdery particles, these processed products can be used in daily life and chemical science and other fields, it can be said that the market is very wide, the demand is also very large, everyone can't do without wheat, everyone can't do without wheat No corn. Therefore, there is no mistake in choosing this line. If there is demand, there will be a market.